Princess Peach's Castle is a stage that appears in Super Smash Bros. Melee, and its appearance is heavily based upon Princess Peach's actual castle. Unlike the Peach's Castle stage from Super Smash Bros., in this stage, players fight on the roof of the actual palace. This time, numerous colored switches and ! Blocks appear every once in a while, and they might either create blocks that can release items (except heavy items) if attacked or jumped from below, create extra platforms, or act as a platform themselves, by hovering over the edge. Banzai Bills frequently bombard the rooftop at random intervals, and they will cause massive damage and knockback to anyone caught in the blast.

Princess Peach's Castle is also featured in Adventure Mode, where the player, after passing through the Mushroom Kingdom, battles both Mario and Princess Peach on the stage. If the end time of the previous Mushroom Kingdom stage ends with a two in the individual seconds, Luigi will appear instead of Mario and a small cutscene plays involving Luigi's knocking Mario away and defeating him.

In the castle, a small drain entrance at the bottom right-hand corner can be seen, which is likely to be a reference to the door at the castle moat from the original Super Mario 64.

Princess Peach's magnificent royal castle appears to be inhabited solely by the princess and a multitude of Toads. Bowser tried to steal the castle's Power Stars in Super Mario 64, and in Paper Mario, the surly archfiend actually lifted the castle into the stratosphere with his own filthy fortress.